Lecture 8 Flashcards
Which of the following is a major environmental cost of pesticide use?
A. Increased crop yields
B. Accumulation of organic matter in soil
C. Contamination of groundwater and biomagnification in food chains
D. Development of natural pest resistance
C
Explanation: Pesticides can persist in the environment, biomagnify in food chains, and contaminate water sources, leading to significant environmental harm.
What is the primary goal of Integrated Pest Management (IPM)?
A. Complete eradication of pest species
B. Use of maximum pesticide levels to maintain crops
C. Reduction of pest populations to economically and ecologically justified levels
D. Sole reliance on biological control methods
C
Explanation: IPM aims to balance pest control with ecological and economic sustainability, minimizing pesticide usage while maintaining healthy crops.
Explain how agricultural intensification contributes to pest problems.
Agricultural intensification simplifies ecosystems, creating monocultures that are more vulnerable to pest outbreaks. It reduces natural predators and biodiversity, leading to greater reliance on artificial pest control methods.
Explanation: Diverse ecosystems naturally regulate pest populations. Simplified systems, like monocultures, disrupt these balances.
What are the potential consequences of pesticide resistance in pests?
Pesticide resistance can lead to increased crop losses, higher pesticide costs, and environmental damage due to the overuse of stronger chemicals.
Explanation: Resistance occurs when pests adapt, rendering pesticides ineffective and forcing reliance on alternative or more toxic options.
Describe two types of crop losses caused by pests.
Quantitative losses: Reduced yield per unit area due to pest damage.
Qualitative losses: Lower market quality, contamination, or reduced valuable ingredients in crops.
Explanation: These losses affect both the quantity and quality of agricultural produce, impacting food security and market value.
Analyze the role of biological control in addressing pesticide resistance.
Biological control can reduce reliance on chemical pesticides by using natural predators or pathogens to manage pest populations. This method prevents the selection pressure that drives resistance in pests.
Explanation: By maintaining a balanced ecosystem, biological control minimizes pest resistance and supports sustainable agriculture.
Evaluate the trade-offs between chemical pest control and biological control methods.
Chemical control offers quick and widespread pest elimination but causes resistance, environmental harm, and non-target effects. Biological control is slower and less predictable but sustainable and minimizes ecological disruption.
Explanation: Both methods have benefits and limitations; integrating them in IPM can optimize pest management.
How do persistent organic pollutants (POPs) from pesticides impact marine ecosystems?
POPs bioaccumulate in marine food chains, leading to toxicity in marine animals, loss of biodiversity, and disruption of ecosystem services.
Explanation: Their low water solubility and high persistence make POPs a significant threat to aquatic environments.
Case Study: White-nose Syndrome in North American bats. Question: Discuss the ecological and agricultural impacts of bat population declines caused by white-nose syndrome.
Bats are key predators of agricultural pests. Their decline has led to increased insecticide use, higher crop protection costs, and loss of biodiversity.
Explanation: The disease has cascading effects, disrupting natural pest control and increasing reliance on chemical interventions.
Case Study: Glyphosate Resistance in Weeds.
Question: How has glyphosate resistance affected agricultural practices in the United States?
Glyphosate resistance has led to increased weed control costs, reduced crop yields, and the development of alternative weed management strategies.
Explanation: Overuse of glyphosate has selected for resistant weed species, requiring more integrated approaches.
Case Study: Pesticide use in apple orchards.
Question: What seasonal pesticide applications are used in apple orchards, and what are the potential risks?
Herbicides in autumn, fungicides and insecticides in winter and spring, and insecticides in summer. Risks include resistance development, non-target impacts, and environmental contamination.
Explanation: Seasonal strategies aim to protect yields but come with significant environmental trade-offs.
How does IPM integrate biological control with other pest management techniques?
IPM uses a combination of biological agents, physical methods, and minimal chemical use, guided by cost-benefit analyses.
Explanation: This integration maximizes effectiveness while reducing ecological and health risks.
Why is biodiversity important in natural pest control?
Biodiversity provides a range of natural enemies to pests, maintaining ecological balance and reducing outbreaks.
Explanation: Diverse ecosystems support predators and parasites, limiting pest populations without artificial interventions.
What factors hinder the adoption of biological control in global agriculture?
Barriers include farmer attitudes, regulatory limitations, high initial costs, and dependence on traditional chemical methods.
Explanation: Overcoming these challenges requires education, policy changes, and economic incentives.
What are the key differences between inoculative and inundative biological control?
Inoculative control relies on the natural multiplication of released agents, while inundative control depends on the immediate impact of the released population.
Explanation: These approaches differ in their reliance on reproduction for long-term pest suppression.
Describe the concept of conservation biological control and provide an example.
Conservation biological control involves protecting and enhancing natural enemies of pests, such as providing refuges or selective pesticide use. Example: field margin seed strips for natural predators.
Explanation: This method emphasizes creating an environment conducive to biological control agents.
What are hyperparasitoids, and why are they a challenge in biological control?
Hyperparasitoids attack primary parasitoids, reducing their effectiveness in pest management.
Explanation: They disrupt the balance of biological control systems, requiring careful management to mitigate their impact.
Discuss the role of herbivore-induced plant volatiles (HIPVs) in pest management.
HIPVs attract natural enemies of herbivores, enhancing biological control by signaling predator presence.
Explanation: These plant mechanisms can be harnessed to support sustainable pest management practices.
How does pesticide use affect pollinator populations and crop pollination?
Pesticides reduce pollinator populations through toxicity, leading to decreased crop pollination and economic losses.
Explanation: Pollination is vital for many crops, and pesticide impacts can threaten food security.
Evaluate the long-term sustainability of IPM compared to chemical control.
IPM is more sustainable as it reduces resistance, environmental harm, and reliance on chemicals, though it requires greater knowledge and initial effort.
Explanation: Its focus on ecological balance and multiple control methods supports resilience in agricultural systems.
